Types Of Pavements & Its Design

Contents Types of Pavement Factors Affecting Selection of Pavement Pavement Components Factors to be Considered in Pavement

Design Flexible Pavement Design Methods Rigid Pavement Design Methods

Flexible Pavement

Called "flexible" since the pavement possess low bending strength and can transfer the wheel loads on the soil subgrade below by deformation action .

Eg: Bituminous and WBM roads

Rigid Pavement

Called “rigid” since the pavement possess good bending strength and can transfer the wheel loads on the soil subgrade below without deformation .

Eg: Cement concrete and RCC roads

Types Of Pavements

Flexible PavementsStructure

Surface courseBase courseSub-base courseSubgrade

StructureSurface courseBase courseSub-base courseSubgrade

Rigid Pavements

1. Type and intensity of traffic2. Availability of funds3. Subgrade soil and drainage conditions4. Availability of construction materials5. Availability of equipments, skilled and

unskilled labour6. Atmospheric conditions7. Time available for project completion8. Level of the area above mean sea level

Factors Affecting Selection Of Pavements

1. Subgrade2. Sub-base3. Base course4. Wearing course or Surface course

Pavement Components

1. Design wheel load

2. Subgrade soil

Factors To Be Considered In Pavement Design

3. Design life

4. Climatic factors

5. Pavement component material

6. Environmental factors

7. Drainage

8. Road geometry

1. Group Index method (G.I. method)2. CBR method3. California R value method4. Triaxial test method5. Burmister method6. Mcleod method

Flexible Pavement Design Methods

This method evolved from the soil classification methodsand was entirely empirical in its approach. • The Group Index (GI) is defined as: GI = 0.2a + 0.005ac+0.01bd

a = F - 35 (maximum 40) b = F - 15 (maximum 40) c = wL - 40 (maximum 20) d = Ip - 40 (maximum 10) F = Percentage by mass passing through 0.75mm, expressed

as a whole number

wL = Liquid limit(%) expressed as a whole number

Ip = Plasticity(%) expressed as a whole number

Group Index Method

CBR Method